Which natural hormone suppresses the release of serotonin and other vasoactive substances from carcinoid tumors?

Which natural hormone suppresses the release of serotonin and other vasoactive substances from carcinoid tumors?

• A. Somatostatin
• B. Histamine
• C. Aldosterone
• D. Vasopressin

Answer: (A)

Somatostatin is a natural peptide hormone that broadly suppresses the release of many hormones and mediators. In carcinoid tumors, the malignant enterochromaffin cells release serotonin and other vasoactive substances into the bloodstream. Somatostatin acts on receptors on these tumor cells to inhibit exocytosis, reducing how much serotonin is released. This dampening effect helps prevent the flushing, bronchospasm, and hemodynamic instability characteristic of carcinoid syndrome, and it’s why somatostatin or its analogs (like octreotide) are used clinically to blunt tumor secretions during anesthesia and reduce the risk of carcinoid crisis. The other substances listed don’t perform this suppressive role for serotonin release: histamine itself is a mediator rather than a suppressor, aldosterone governs salt and water balance, and vasopressin regulates fluid retention—none of them specifically inhibit serotonin release from carcinoid tumors.

Somatostatin is a natural peptide hormone that broadly suppresses the release of many hormones and mediators. In carcinoid tumors, the malignant enterochromaffin cells release serotonin and other vasoactive substances into the bloodstream. Somatostatin acts on receptors on these tumor cells to inhibit exocytosis, reducing how much serotonin is released. This dampening effect helps prevent the flushing, bronchospasm, and hemodynamic instability characteristic of carcinoid syndrome, and it’s why somatostatin or its analogs (like octreotide) are used clinically to blunt tumor secretions during anesthesia and reduce the risk of carcinoid crisis. The other substances listed don’t perform this suppressive role for serotonin release: histamine itself is a mediator rather than a suppressor, aldosterone governs salt and water balance, and vasopressin regulates fluid retention—none of them specifically inhibit serotonin release from carcinoid tumors.